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Swapping gears in the t86

Discussion in 'Early CJ5 and CJ6 Tech' started by B_hester, Apr 24, 2015.

  1. B_hester

    B_hester Member

    Hello folks. My jeep is geared so tight it only goes 50 mph with the 225. I was wondering if there was a way I could swap the 3rd gear that has a 1:1 ratio for something even smaller like 0.8:1 (not sure if that actually is one im just trying to give an example) has anybody done this sort of thing before? Or atleast have any ideas? Thanks guys
     
  2. Jw60

    Jw60 That guy 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Add a warn or saturn overdrive. The transmission doesn't have a 3rd gear to remove as it locks the input and output together
     
  3. B_hester

    B_hester Member

    Thanks! That's actually extremely helpful!
     
  4. Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

    The 225V6 with the T86 will run down the hiway 85-90 all day with 3:73 gears. What ratio is the rear-end/front-end. That is what is slowing you down.
     
  5. Glenn

    Glenn Kinda grumpy old man Staff Member

    You sure the speedometer doesn't read low? An F-head Jeep with 5.38's will go 60. Have you had someone follow you in a car maybe to see how fast you are going?
     
  6. B_hester

    B_hester Member

    I've got the 4.88 gears but I'm content with the power they bring. I realize changing them would give me the speed, but I was hoping I could do it with those still in
     
  7. B_hester

    B_hester Member

    I haven't had anybody follow me but I've looked up the speed calculators for the dauntless motor. They all say that the max speed with my gears would be about 52
     
  8. Glenn

    Glenn Kinda grumpy old man Staff Member

    What diameter/size tires do you have, and what rpm's did you use for the calculation?
     
  9. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Tall tires and 4.88s should be fine for highway speeds. I recall a friend in the day that would run the aviation rib tires (33s?) and 4.88s ('71 225) on the SoCal freeways in the day and drive highway speeds just fine.

    Try the Novak gearing calculator. http://www.novak-adapt.com/knowledge/gearing.htm Your transmission's final drive ratio is 1.0. 3000 RPM is not an unreasonable cruising speed for a healthy 225.

    Maybe you are unaccustomed to the amount of gear and road noise that you have in a Jeep.
     
    Last edited: Apr 28, 2015
  10. B_hester

    B_hester Member

    I only have 31'
     
  11. B_hester

    B_hester Member

    Oh and I used 2900 rpm for calculations
     
  12. B_hester

    B_hester Member

    Even that calculator only said 57 mph at 3000 rpm. Any faster rpm for prolonged amounts of time risks damaging the engine severely!
     
  13. Glenn

    Glenn Kinda grumpy old man Staff Member

    Well, the less the rpm's at a given speed the better, so you might as well get an over drive! No doubt they're worth the cost. :)